Putting boots on the (dung-like, muddy) ground of Seymour Island, Antarctica
Published: February 17, 2011
David Rusak, Walrus Magazine
The most dedicated members of the Antarctic University Expedition 2011 roused themselves at 5 a.m. today to witness our entry into the Weddell Sea, the great, ice-riddled body of water from which we will be visiting the Antarctic Peninsula and surrounding islands. Several wildlife sightings and a breakfast later, we got the news we were waiting for — the winds were high, but we would still be able to make our first landing on Antarctic soil today. The expedition’s ship, the Ushuaia, took us within a few kilometres of shore; we made the rest of the way on Zodiacs that manoeuvred us through the intervening field of icebergs. Conditions were choppy as advertised, and we stepped rather wetly out of the boats and onto a short beach overlooked by slanting cliffs. We had arrived on Seymour Island.
The geology students in our midst immediately set about examining the rock face. Our reason for choosing this rather obscure island had to do with their field of interest: it is one of few places on Earth known to preserve a fossil record encompassing the transition between the Cretaceous and Tertiary periods of geologic time — and, of course, it is the southernmost of that group of about twenty. This transition, called the K-T Boundary, is better known to the rest of us as the mass extinction that ended the era of the dinosaurs 65 million years ago, ushering in the Cenozoic era we occupy today. The cause of this tremendous upheaval remains contested, and, according to one of our experts, Carleton professor of Earth sciences Claudia Schröder-Adams, what can be found on Seymour Island plays a significant role in the debate.
To one not versed in the analysis of sediment, however, the dominating impression of the island is of hills of muckiness. Nearly every surface we encountered was covered in a dung-like layer of mud, sometimes perilously thin over ice. This accumulated stupendously on our boots as we trudged across the hills and valleys that glaciers have carved out of the landscape. The geologists became our oracles on this trip: the rest of us consulted constantly those who could unlock the secrets of a curious sheet of rock or parallel lines in the mud.
Our goal was to find the K/T Boundary, and perhaps some telling fossils therein. (I found this way of saying it, “finding the boundary,” off-putting, unused to the palaeontologist’s habit of reading the passage of time inscribed in space.) We were looking for bands of the mineral glauconite, which would point out the transition zone between the periods. After a while’s wandering inland, Claudia became convinced that the opposite wall of the valley that we stood in showed just those bands, with finer Cretaceous soil beneath and dry Tertiary sandstone above — the knifing of a glacier having laid bare these millions of years of accumulation. Sure enough, closer examination vindicated her hypothesis, and the students dispersed, scouring the hill for fossils.
Claudia, who pushed for this trip, was clearly overjoyed — not least because of the pressure on her to get some results. And while we certainly had neither the time nor the resources to do any kind of systematic survey, with her students bringing back fossils from all over (ancient molluscs embedded in petrified tree sections, well-preserved bivalves, etc.), she grinned and enthused about the fact that we were really there — result enough.
Our group’s other paleo expert, Natalia Rybczynski, debriefed us later on some of the strange and wonderful Tertiary creatures we might have missed encountering on the other side of the Boundary and island. The fossil-lovers lingered on the site, picking things up and discussing them excitedly, after the rest of the group had gone back to our boats. After being gently urged that it was past time to return, they lingered a bit longer. I can’t blame them.
Original source taken from: Walrus Magazine